Mark As Legacy Animation...

So, i need to mark as Legacy an Animation, but the AnimationClip is read-only, because it’s an FBX.
I got it from the Assets Store. What can i do?

Have you tried to select the FBX and set the property “Animation Type” to “Legacy” in the Rig settings?

You can try switching the inspector of the animation clip to “debug” and then you will see the legacy toggle and will be able to activate it.
If that doesn’t work go into animation view and copy all the key frames into a new animation asset created in Unity, save it and then try setting the legacy toggle on it.